The present disclosure relates to systems for cooling electronic and other heat-generating equipment, and more particularly to systems for cooling the air flowing in proximity to electronic equipment configured in vertical banks in a rack or cabinet.
The growth of the computer industry over the past few decades has been phenomenal. Many new computer designs combine multiple computer/processor boards to make “high end” computers and “servers”. Due to the demand for floor space, computer boards are often configured to be “stacked” vertically in a rack or cabinet. Many existing cooling systems for electronic equipment contained in such a vertical rack do not provide adequate cooling. In many of these cooling systems, air is drawn into the bottom of the rack or cabinet containing computer boards and moved vertically through the cabinet, progressively cooling the respective computer boards. In this design, the boards mounted “higher” in the rack receive warmer air than those mounted toward the bottom because the air has already passed over and absorbed heat from one or more boards. Consequently, the “higher” boards are not adequately cooled by the flow of warmer air.
At the same time, newer, more powerful microprocessors are constantly being introduced, but this higher performance is generally accompanied by significantly increased heat generation. Thus, these newer processor configurations are driving up heat loads to the point that “unaided” air cooling cannot provide enough capacity to keep these “stacked” computers from overheating. As a result, “stacked” servers may have to operate at reduced processing speeds to limit the heat load, which in turn compromises performance.
In addition, existing cooling systems have a rather limited cooling capability. For instance, many existing cooling systems have heat densities of approximately 80 watts per square foot (W/ft2), though some cooling systems still under development are said to possess heat densities of up to 150 W/ft2. Even cooling systems having these heat densities, however, may not effectively cool today's state-of-the-art electronic equipment.
As is readily apparent, if equipment is not sufficiently cooled, the internal temperature of the electronic components in the equipment dramatically increases over relatively short periods of time, which may result in significantly reduced system performance and, in some cases, component or total system failure. Even where system performance is not compromised, inefficient cooling may unnecessarily increase the cost of cooling the equipment. Thus, there remains a need for a cooling system that adequately and efficiently cools computer boards configured in vertical banks in a rack.